LAMELUBRANCHIATA. 



If these suppositions prove to be well-founded, the synonymy of the Atlantic form will then 

 be as follows: 



Pecten undatus Verrill & Smith 1 ). 

 1876. Pecten fragilis Jeffreys, Ann. Mag. Nat. Hist. (4) XVIII, p. 424 (partim). Northern Atlantic 



(between Ireland and Greenland), 1450 — 17S5 fin. 

 1879. P-fragilis Jeffreys, Proc. Zool. Soc. Lond. p. 561 (partim) (non PI. 45, fig. 1). - W. of Ireland, |.2ofm. 

 18S5. P.undatus Verrill & Smith, Trans. Conn. Acad. VI, p. 444, PI. 44, fig. 21. Off Virginia, 



1423 fm. 

 1885. P.pudicus E. A. Smith, Chall. Rep., XIII, Bamellibranchiata, p. 302, PI. 21, fig. 8. -■ Southern 



Ocean E. of Marion Island, 1375 fm. 

 1888. P.biscayrusis Locard, Contrib. a la fauue malacologique francaise, XI Monogr. des esp. app. 



an Genre Pecten, p. 144. -- Bay of Biscay, "/ones profondes". 



1897. Chlamys (Pseudamussium) pudica Dautzenberg & Fischer, Mem. Soc. Zool. de France, 



p. 191. — Azores, 1846 fm. 

 1S98. Pecten Biscayensis Bo card, Exped. scient. du Travailleur et du Talisman, Moll. Test. II, p. 400. 

 — N. of Spain, 1353 m.; off Santander, 1960111.; W. of Soudan, 2635 m. 



1898. Hyalopecten dilectus Verrill & Bush, Proc. Unit. Stat. Nat. Mus., 20, p. S36, PI. 97, fig. 9. 



Off Marthas Vineyard, 1813 fm. 



1899. H. dilectus Verrill & Bush, Trans. Conn. Acad., X, p. 90. 

 1899. H. undatus Verrill & Bush, ibid., PI. 18, fig. 5. 



To this species I refer a fragment of a left valve, taken by the "Ingolf" at 

 St. 1 8. Entrance to the Denmark Strait 1135 fm. 3.0 C. 



Pecten maximus Linne. 

 Ostrea maxima Linne, Syst. Nat. ed. 12, 1, 2, 1767, p. 1144. — Pecten maximus Jeffreys, Prit Conchol. II, 

 1863, p. js, PI. 24. 



A fragment, ancient in appearance, of a large valve (the ventricose right valve) was obtained 

 by me in the dredge on Faeroe Bank (6o°55'N. P., 8°56' W. P.) at a depth of 69 fm. 



Distribution. The Western Mediterranean 2 ) and along Europe from the Canary Isles and 

 Madeira to Scotland, Southern Norway, Skager Rak and Bohuslan. 



Amussium lucidum Jeffreys. 



PI. II, figs. 3a — c. 

 Pleuronectia lucida Jeffreys, in Wyville Thomson's Depths of the Sea, [873, p. 464, fig. 



Amussium lucidum Jeffreys, Ann. Mag. Nat. Hist. (4) XVIII, [876, p.425; Jeffreys, Proc. 



') Tlie name Pecten fragilii Jeffreys cannot be taken into consideration, as 011 the one hand, .is shown, it embraces 

 heterogenous forms, on the other it lias been used, as Locard has shown, both by Chemnitz ami by Montagu for other 

 species. More doubtful is the question between the names undatm and piid/'cus, as they wen- brought into use in the same y< 



-) Cf. Monterosato: Revision de quelques Pecten des mers d'Europe (Jouni. de Conchyliologie, [S99, Nr. 3, p. 4). 



i) Dall is of opinion, that only the figure to the left represents A. lucidum, whereas the figure to the right 

 of another species, namely A. Pourtalesianum ; Bull. Mus. Comp. Zool., vol. XII, No. 6, p 211. 



